I'm thinking about wiring up a dual battery set up and just curious how you guys are doing it. I'm thinking that an in-series setup would work fine but would setting the batteries up in parallel work better? Also, I was also thinking about maybe doing an interconnect/disconnect with a switch. Thoughts? Thanks.

i have another question to piggy back
i already have a 10" sub and i am thinking about getting a winch and maybe some lights
at what point would i need to install dual batteries
or maybe should i just go with aditional or stronger alternator ?

Both of you guys better get some DC theory Down............Series is 24V unless this is a nato vehicle or a Govt issued Hummer, You had better stick to parallel.

http://www.wranglernw.com/ShowCategory.aspx?categoryid=843

Here is alink to what I use. Good luck and dont be afraid to ask questions like this. these are simple but important question. Flame On!!!!:mad3:

Should've clarified, but thanks for pointing it out. If I go in series I would use a transformer to step it down to 12V (the inverse current relationship deal), I'm more concerned with amperage draw and by that, from experience which would be better? I'm in the process of a rebuild and with a winch (and possibly onboard welder) and all the added stuff I'm planning on installing I'm wondering what would work better amp-hour wise. I do intend to install a higher rated alternator for when it's running, but there are times when the engine might be off so I don't want to drain the batteries out in BFE.

I run two deep cycle (yellow) Optimas. Never failed me yet.....and I run my stereo boomin for hours........I ve got an old cop motor so it already has a high output 120amp alt. The biggest foul I see on the trail is guys that dont run the right size cabling for the Batteries. I solder all my connections and none have failed, I have seen crimps cause problems over and over. Remember heat shrink is your friend......BTW a stay away from transformers...just more shit to break and not necessary

Yes crimp and solder all connections , I run two smaller cables just easier to work with , red & yellow Optimas with breakers , two alternators one used as welder and 700A continues marine battery switch , do it right once .
http://i136.photobucket.com/albums/q188/ditchpig_photo/83CJ7008.jpg

Yes crimp and solder all connections , I run two smaller cables just easier to work with , red & yellow Optimas with breakers , two alternators one used as welder and 700A continues marine battery switch , do it right once .

I like the look of your setup Ditchpig. What does the other side of the firewall look like? Where do those big cables go?

If I go in series I would use a transformer to step it down to 12V (the inverse current relationship deal), I'm more concerned with amperage draw and by that..........................:confused: You should know that a transformer only works with ac current It will only work on dc when you turn it off. Try it with a 9volt battery and see for your self.

insanebikerboy and onegreentj;

I'm also in the middle of planning a fairly substantial electrical upgrade for a winch and onboard welding. If we are all doing that, and we are all fairly local (a guess from onegreentj's thread) then we might wanna' get together on this. At the very least I'll volunteer to help either/both of you out on your rig so that I can get some experience.

I like the look of your setup Ditchpig. What does the other side of the firewall look like? Where do those big cables go?

They go to the battery selector switch , O/P of that goes to fuse block inside and to a B+ stud under hood and another fuse block . As you can tell there are no heater ducts but it can be done with everything still in place .
http://i136.photobucket.com/albums/q188/ditchpig_photo/83CJ70062.jpg
http://i136.photobucket.com/albums/q188/ditchpig_photo/83CJ7007-1.jpg

If I go in series I would use a transformer to step it down to 12V (the inverse current relationship deal), I'm more concerned with amperage draw and by that..........................:confused: You should know that a transformer only works with ac current It will only work on dc when you turn it off. Try it with a 9volt battery and see for your self.

Actually, have to disagree with you on that point, otherwise, how does your cell phone charge when plugged in to a cigarette lighter (or anything else you might power from the lighter, i.e., dvd player, laptop, which are all dc, and will run when the car is on or off).

However, I had said something about interconnects/disconnects, as I was envisioning being able to remove one battery from the line when the engine is running. Might be too much work, I'm just trying to get ideas from all points.

@Fozzy Bear, I'm in Florida so I don't think it'd be possible to do that.

Should've clarified, but thanks for pointing it out. If I go in series I would use a transformer to step it down to 12V (the inverse current relationship deal),


Unbelievable. :shaking: A transformer doesn't work with DC. Try again.

Actually, have to disagree with you on that point, otherwise, how does your cell phone charge when plugged in to a cigarette lighter (or anything else you might power from the lighter, i.e., dvd player, laptop, which are all dc, and will run when the car is on or off).

However, I had said something about interconnects/disconnects, as I was envisioning being able to remove one battery from the line when the engine is running. Might be too much work, I'm just trying to get ideas from all points.

@Fozzy Bear, I'm in Florida so I don't think it'd be possible to do that.

because there are other things inside of it beside a transformer

Unbelievable. :shaking: A transformer doesn't work with DC. Try again.

Meaning the same thing but speaking different language, the correct technical term is converter, so my bad on calling it a transformer (old habits die hard). However, they do the exact same thing.

Either way, what you guys think about it? Is the current draw even worth messing with series or just go with straight up parallel?

va beach is not for sure yet
but it is either that or blairsville pa (for wyo tech)
either way it is still going to be a while before im up there
hell im still in japan right now

...
either way it is still going to be a while before im up there
...

No Problem, Like I said, I'm still just planning...

[QUOTE=ditchpig;6332170]Yes crimp and solder all connections, do it right once .

Your advise would be more credible if your picture didn`t show your use of the totaly worthless clamp/repair style battery terminal ends. :shaking:

Don't have a picture of my setup with me (I'll see if I can find one), but:

- Optima Red Top for main battery
- Optima Yellow Top for all accessories
- Painless Wiring Isolator (http://www.painlesswiring.com/InfoSearch/partnumber_list.php?SearchField=40102)
- Mean Green 200Amp Alternator (http://www.mean-green.com/products/alternator.html)
- ~20' of red and 20' of black #2 stranded cable
- other: heat shrink, lugs, and wire ties

I set mine up some time ago with the mindset that everything that came stock with my TJ went to the main battery and everything I've added (lights, winch, CB, etc) go on the accessory battery.

Here's a pic of how its wired...

http://farm1.static.flickr.com/150/352978684_57be60e78f.jpg?v=0

I know there are other ways to do it, but this one has worked quite well for me.

...
everything that came stock with my TJ went to the main battery and everything I've added (lights, winch, CB, etc) go on the accessory battery.

Here's a pic of how its wired
...

So, I would guess then there is another fuse box (connected to the second battery) that is not in your picture for all the new stuff?

Thanks for the link, by the way.

.

I thought an isolator was nothing but grouped diodes, an alternator lead in and 2 leads out (one for each battery)?

So, I would guess then there is another fuse box (connected to the second battery) that is not in your picture for all the new stuff?


Sort of...I'm going to move to that point, but as of right now, each new thing on the Aux side has its own fuse as provided by the given manufacturer.

I thought an isolator was nothing but grouped diodes, an alternator lead in and 2 leads out (one for each battery)?

I believe that is about right. The nice thing about the painless one is that there is a connection into the cab (not shown on the pic) with a switch that can allow for 1) normal operation where both batteries are being charged, 2) splitting off the Aux battery so it is completely by itself (i.e. not being charged), and 3) connecting the two batteries together in case the main is dead and you need to basically do jump it (with no jumper cables) to start the vehicle.

Meaning the same thing but speaking different language, the correct technical term is converter, so my bad on calling it a transformer (old habits die hard). However, they do the exact same thing.

Either way, what you guys think about it? Is the current draw even worth messing with series or just go with straight up parallel?

You obviously are more concerned about current so a series circuit is NOT what you want to do. Current is additive in a parallel circuit, Voltage is additive in a series circuit. Parallel your batteries and be done with it. any other means would create electrical losses.

An NO, transformers for the most part are not used in D.C. circuits to reduce voltage. The device you plug into your cigarette lighter to charge your cell phone uses a voltage deviding circuit or zenier diodes or some other regulating circuit to reduce D.C. voltage from 12VDC to 3VDC, (cell phone voltage) not transformers.

Sort of...I'm going to move to that point, but as of right now, each new thing on the Aux side has its own fuse as provided by the given manufacturer.

Oh.
So you have a sort-of Satan's pigtail mess thingie that you've been meaning to get around to cleaning up. MeThinks I've found a kindred spirit. :D

[QUOTE=ditchpig;6332170]Yes crimp and solder all connections, do it right once .

Your advise would be more credible if your picture didn`t show your use of the totaly worthless clamp/repair style battery terminal ends. :shaking:

Like I said do it right once not the secound time like me , as you can tell I ran out and used the clamp ones to go wheeling it is all crimped and soldered now , that was when I installed the battery breakers due to the original battery mount breaking turned side ways and the cable got pinched and cut into the frame it was a nice shower of sparks as I was trying to pull the cable out .

Actually remembered to find the pic I mentioned...

Here ya go:

http://farm1.static.flickr.com/124/353318613_5e79738e24.jpg?v=0

While we're at it, here's a pic of the "tray":

http://farm1.static.flickr.com/159/353324663_2c43d68673.jpg?v=0

And the top bracket:

http://farm1.static.flickr.com/140/353324666_4ed6d80cfe.jpg?v=0

Uses the stock J bolts to hold it down.

And I used about 1/2 a can of spray on bed liner to coat the metal cross bar (figured it might make a nice rubberish coating on the cross bar).

The two ends of the cross bar that aren't touching the J bolts are bent at a 90 degree to stop the batteries from shifting side to side.

In all was a fun project...especially since it was my first. :smokin:

Are yins guys making custom battery boxes/trays? any pics of them without the batteries installed?

Uhm...see post #27, above...

Anybody bother to read the tech section? http://www.pirate4x4.com/tech/billavista/dual_battery/my_dual_battery_setup.htm

Some people say that if both batteries are not the same, ie Deep Cycle v/s cranking battery, that they will "fight" each other, but I'd say as long as you have them isolated properly then that shouldn't happen. There is a lot of good information (and switches, isolators, etc) from boats, check online, or your local boat shop (West Marine, etc) for dual battery kits, cool switch panels, etc.

Anybody bother to read the tech section? http://www.pirate4x4.com/tech/billavista/dual_battery/my_dual_battery_setup.htm

Some people say that if both batteries are not the same, ie Deep Cycle v/s cranking battery, that they will "fight" each other, but I'd say as long as you have them isolated properly then that shouldn't happen. There is a lot of good information (and switches, isolators, etc) from boats, check online, or your local boat shop (West Marine, etc) for dual battery kits, cool switch panels, etc.

Read that, but it just looked fugly. Took my drawing (from page one of this thread) and verified it with one of the engineers at Painless Wiring to ensure it would work. He said it would so I continued.

Like I said, have had it installed now for at least 6 months and haven't had any problems with it...

Read that, but it just looked fugly. Took my drawing (from page one of this thread) and verified it with one of the engineers at Painless Wiring to ensure it would work. He said it would so I continued.

Like I said, have had it installed now for at least 6 months and haven't had any problems with it...


Agreed, not BillaV may not be the prettiest, smoothest installation, but I was referring more of the concept.

rketr, your set up looks pretty slick

Uhm...see post #27, above...

Der! I need to wake up and pay attention.... it looks like the angle pieces are just tac welded to the fender and firewall????? or am i not seeing something.... I hope so, i dont think tac welds are gona hold 2 batteries:confused:

Der! I need to wake up and pay attention.... it looks like the angle pieces are just tac welded to the fender and firewall????? or am i not seeing something.... I hope so, i dont think tac welds are gona hold 2 batteries:confused:

hehee...they've worked so far :grinpimp:

Der! I need to wake up and pay attention.... it looks like the angle pieces are just tac welded to the fender and firewall????? or am i not seeing something.... I hope so, i dont think tac welds are gona hold 2 batteries:confused:

The angle really only holds them from shifting. The visible red part in the middle is actually doing all the work holding the weight.